Carpet cleaning apparatus generally consist of a base unit mounted on wheels containing a clean water reservoir, a discharge tank, a pump and a suction motor. A cleaning tool known as a "wand" is connected to the base unit by approximately thirty feet of flexible hose. The pump on the base unit is used to draw water mixed with chemicals from the clean water reservoir to the wand where the water is injected into the pile of the carpet. The suction motor is then activated to draw dirty water from the carpet to the discharge tank.
There are physical limitations on the amount of suction which can be delivered through a 11/2 inch diameter hose to a wand by a small motor. For this reason persons skilled in the art have converted their service vehicles into base units which use the engine of the vehicle to deliver increased levels of suction. There are many applications, such as high rise buildings, where the use of these vehicle mounted units is not practical.